1. Field of the Technology
The present disclosure relates generally to methods and apparatus for establishing and handling voice calls for mobile communication devices to facilitate handovers of the voice calls between heterogeneous wireless networks (e.g. WLAN/802.11/SIP technologies vs. WWAN/cellular technologies).
2. Description of the Related Art
The present disclosure is generally directed to techniques for establishing and handling voice calls for mobile communication devices in order to facilitate handovers of the voice calls between heterogeneous wireless communication networks. A particular focus is directed to voice calls between mobile communication devices and communication devices in the public switched telephone network (PSTN), and inter-enterprise voice calls between communication devices in the same communication network.
A mobile communication device may be adapted for wireless communications via a wireless local area network (WLAN), such as an WLAN utilizing IEEE 802.11 and Voice over IP (VoIP) based communications, as well as a wireless wide area network (WWAN), such as a cellular telecommunications network utilizing Global Systems for Mobile Communications (GSM)/General Packet Radio Service (GPRS) technologies, for example. VoIP is enabled in part by use of a Session Initiation Protocol (SIP). Although SIP-enabled networks carrying VoIP communications are quickly growing as a percentage of the communications market, they still represent a small percentage of the overall voice market. Therefore, such SIP-enabled networks must be able to communicate with other types of networks, especially via the PSTN.
When a voice call involving the mobile communication device and a PSTN destination is established, it is desirable to seamlessly maintain the voice call even though the mobile communication device may switch operation between the WLAN and WWAN. To accomplish this, the voice call may be routed through a conferencing gateway to facilitate the handover of the voice call between the WLAN and WWAN. For voice calls between communication devices of the same private communication network (e.g. the same private LAN of an enterprise such as a company or corporation), however, use of the conferencing gateway may not be necessary in cases where no handover will ever occur. As, apparent, use of the conferencing gateway for all such voice calls creates an unnecessary and undue burden on the conferencing gateway and perhaps unnecessary expense.
Accordingly, there are needs for methods and apparatus to establish and handle voice calls for mobile communication devices to facilitate handovers of voice calls between heterogeneous wireless networks, especially between communication devices of the same communication network, so as to overcome the deficiencies of the prior art.